msgctl.2, semctl.2, shmctl.2: Some small wording improvements for Davidlohr Bueso's patch

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/msgctl.2

@@ -233,12 +233,13 @@ Return a
 .I msqid_ds
 structure as for
 .BR MSG_STAT .
-However, the
+However,
 .I msg_perm.mode
 is not checked for read access for
-.IR msqid ,
-resembing the behaviour of
-.IR /proc/sysvipc/msg .
+.IR msqid
+meaning that any user can employ this operation (just as any user may read
+.IR /proc/sysvipc/msg
+to obtain the same information).
 .SH RETURN VALUE
 On success,
 .BR IPC_STAT ,

man2/semctl.2

@@ -246,12 +246,13 @@ Return a
 .I seminfo
 structure containing the same information as for
 .BR SEM_STAT .
-However, the
+However,
 .I sem_perm.mode
 is not checked for read access for
-.IR semid ,
-resembing the behaviour of
-.IR /proc/sysvipc/sem .
+.IR semid
+meaning that any user can employ this operation (just as any user may read
+.IR /proc/sysvipc/sem
+to obtain the same information).
 .TP
 .B GETALL
 Return

man2/shmctl.2

@@ -249,12 +249,13 @@ Return a
 .I shmid_ds
 structure as for
 .BR SHM_STAT .
-However, the
+However,
 .I shm_perm.mode
 is not checked for read access for
 .IR shmid ,
-resembing the behaviour of
-.IR /proc/sysvipc/shm .
+meaning that any user can employ this operation (just as any user may read
+.IR /proc/sysvipc/shm
+to obtain the same information).
 .PP
 The caller can prevent or allow swapping of a shared
 memory segment with the following \fIcmd\fP values: